Windows 7: Release Candidate 1 Preview

Virtual Windows XP

As we mentioned previously, Microsoft’s big secret unveiled with Windows 7 RC1 is Virtual Windows XP (VXP for short). One of the issues Microsoft has been having in bringing business users over from Win2K and XP to Vista and beyond has been that Windows does not have perfect backwards compatibility. With consumer applications this is not such a big deal since most of those are wide-audience products that get updated regularly, but this is not always the case for business software. Whether it’s some custom in-house application that no one can fix, or a 3^rd party application that just works and can’t be updated, business users sometimes can’t escape the fact that they need to be able to run old applications that don’t work in newer operating systems.

VXP is in essence the bone Microsoft is throwing to business users to allow them to run those old applications while using Windows 7. VXP leverages Microsoft’s existing Virtual PC virtualization software that they acquired several years back, by bundling it with a fully licensed copy of Windows XP SP3 preconfigured for use as a virtual machine. This virtual machine can then be partially integrated in Windows 7 so that applications operating inside of it look and behave like they are actually running on Windows XP, similar in concept to the coherence mode of Parallels or Unity mode of VMware. In this case Microsoft is using RDP to connect to the virtual machine rather than screen scraping the entire desktop like Parallels and VMware do. Microsoft does the same thing for the Windows Home Server Console.

VXP Desktop View

As Virtual PC was already free, the significance of this announcement is not the technical details, but rather that Microsoft is endorsing it as an official solution to backwards compatibility problems. It’s long been expected that Microsoft would do something with Virtual PC as a backwards compatibility solution and this is finally it, albeit in a limited role.

Because of the system requirements and issues raised by relying on a virtual machine of XP, VXP is a last-ditch compatibility solution rather than any kind of primary solution. On the system requirement side, VXP requires a processor with hardware virtualization features, along with at least 256MB of RAM and the disk space needed to run the virtual machine. It’s not too bad for a modern system, but it does rule out an older system that may be suitable for upgrading to Windows 7, but not running VXP on top of that.

VXP Configuration

As for the issues raised by using VXP, first and foremost it’s a complete copy of WinXP, with all of its security deficiencies and bugs. It needs security software, it needs administration, and it needs security updates. This also brings up a matter that Microsoft hasn’t answered yet: what happens when WinXP support ends in 2014? Windows 7 will have support until at least 2020, which means either Microsoft is going to drop support for this component of Windows 7 early (an unprecedented move) or they have to extend XP support to match Windows 7’s support cycle. We’re still trying to get a final answer on this.

It should also be noted that VXP only comes with Professional edition and higher, as it’s not intended to be a consumer compatibility solution. And before anyone gets any ideas, it’s not suitable for playing games – the graphics hardware is the usual emulated S3 Trio 64, and the screen does not refresh nearly fast enough to keep up with any kind of action game. Solitaire may be playable, however.

VXP in integrated mode running IE6

At any rate, Virtual Windows XP is a good solution to some compatibility needs, so long as it’s recognized that it’s not the solution to all compatibility needs. For the handful of business users it’s designed for, we would expect that it does its intended job well. However for non-business users that absolutely must have a virtual machine (and won’t need support from Microsoft), it may be worthwhile to look into a free solution like VirtualBox.

Looking towards the future, there has been a lot of speculation that Microsoft may try to make a big break from the Windows APIs in order to clear out all the cruft and deprecated functions that litter their APIs. This isn’t happening today with Windows 7 and VXP, but integrating a virtual machine is the first stepping stone in making it happen. What Microsoft does after VXP is undoubtedly going to be a matter of great interest.